Infectious diseases include an extensive group of diseases caused by specific pathogenic (pathogenic) pathogens and transmitted from an infected individual to a healthy one. The peculiarities of infectious diseases are their contagiousness (contagiousness), the ability to mass epidemic spread, the cyclical course and the formation of post-infectious immunity. However, these features are expressed to varying degrees in different diseases.
This type of disease develop as a result of a complex biological process of interaction of a pathogenic microorganism with a susceptible macroorganism under certain conditions. There are several periods in the development of infectious diseases: incubation (latent), prodromal (the period of precursors), the period of development of clinical manifestations, the period of the outcome of the disease. The outcome of the infectious process can develop in several ways: convalescence (recovery), lethality, bacterial carrier, transition to a chronic form.
Infectious diseases account for 20 to 40% of the total structure of human diseases. Many medical and microbiological disciplines are engaged in the study, treatment and prevention of infections: actually infectious diseases, epidemiology, venereology, urology, gynecology, therapy, phthisiology, otolaryngology, immunology, virology, etc.
The number of infectious diseases known to science is constantly increasing and currently has more than 1,200 units. During his life, a person comes into contact with a huge number of microorganisms, but only 1/30000 of this community is capable of causing infectious processes. Viruses, rickettsias, bacteria, fungi have pathogenicity properties.
Depending on the location of the predominant localization of the process and a certain mechanism of transmission, infectious diseases are divided into intestinal (dysentery, cholera, salmonellosis, escherichiosis, paratyphs A and B, typhoid fever, food toxicoinfections); respiratory tract infections (ARVI, influenza, chickenpox, measles, mycoplasma respiratory infection); external integuments (erysipelas, anthrax, scabies); blood infections (HIV infection, malaria, yellow fever, recurrent and typhus); infections with multiple transmission routes (enterovirus infections, infectious mononucleosis).
By the nature of the pathogen, infectious diseases are distinguished: viral (viral hepatitis A, B, D, E and C, influenza, rubella, measles, cytomegalovirus and herpes infections, HIV infection, meningococcal infection, hemorrhagic fevers); bacterial (staphylococcal and streptococcal infection, cholera, salmonellosis, plague, dysentery); protozoal (malaria, trichomoniasis, amoebiasis); mycoses or fungal infections (aspergillosis, candidiasis, epidermophytia, cryptococcosis).
Infectious diseases are divided into anthroponotic and zoonotic. Anthroponoses include infections peculiar exclusively to humans and transmitted from person to person (smallpox, diphtheria, typhoid fever, measles, dysentery, cholera, etc.). Zoonoses are animal diseases that can also infect humans (foot-and-mouth disease, anthrax, rabies, tularemia, plague, listeriosis, leptospirosis, brucellosis).
Diseases caused by pathogens of animal origin – parasites (ticks, insects, protozoa) are called invasive or parasitic.
Among infectious diseases, there is a group of particularly dangerous (quarantine) infections with a high degree of contagion, a tendency to rapid spread, a severe epidemic course and a high risk of death in the shortest possible time from the moment of infection. Plague, smallpox (considered eradicated in the world since 1980), cholera, yellow fever (and similar epidemiology of Marburg fever and Ebola) are classified as particularly dangerous infections by the World Health Organization. Tularemia and anthrax are also classified as particularly dangerous infections in our country.
Treatment of patients with infectious diseases is carried out in specialized hospitals or departments, in mild cases – at home. A prerequisite for the successful treatment of infections is compliance with a strict anti-epidemic regime. The prevention of most infectious diseases is the observance of sanitary and hygienic rules and specific immunization.
The medical directory of diseases posted on the website “Medic Journal” contains a special section – where you can find useful information about the causes, mechanisms of development and clinical manifestations of infections, as well as about modern diagnostic and therapeutic techniques used in this field of medicine.
Rubella is an acute viral infection, manifested by characteristic rashes on the background of moderate intoxication, accompanied by regional lymphadenopathy and hematological reaction. The rubella virus is introduced into the body through the mucous membrane of the respiratory tract, where it enters with inhaled air. The incubation period lasts from 10 to 25 days. Typical…
Measles refers to acute viral infectious diseases, characterized by a combination of catarrhal symptoms with specific exanthema. The measles virus enters the body by airborne droplets. The incubation period lasts up to 2 weeks, sometimes up to 1 month. The catarrhal period of measles is manifested by cough, fever, cervical lymphadenitis. It is replaced by…
Coronavirus is an acute infectious pathology with a predominantly aerogenic mechanism of infection caused by an RNA-containing coronavirus. Specific for coronaviruses is the defeat of the upper respiratory tract, less often – the intestines and stomach. Clinically, the infection is manifested by moderate fever and symptoms of intoxication. Diagnosis of the pathological process involves the…
Whooping cough is an acute infectious disease of bacterial nature, manifested in the form of attacks of spasmodic cough accompanying catarrhal symptoms. Infection with whooping cough occurs by aerosol in close contact with a sick person. The incubation period is 3-14 days. The catarrhal period of whooping cough resembles the symptoms of acute pharyngitis, then…
Cutaneous leishmaniasis is an infectious disease caused by protozoa and accompanied by damage to the skin, less often the mucous membranes. A characteristic feature is ulcers at the site of the introduction of the pathogen. The temperature reaction of the body varies widely, other signs of the disease are detected very rarely. Diagnosis is based…
Clonorchiasis is a chronically occurring helminthic invasion. The main symptoms are associated with the involvement of the liver and pancreas; with a significant duration of the disease, cirrhotic changes, acute pancreatitis may occur, and the likelihood of malignant neoplasms of the hepatobiliary system increases. Allergic reactions caused by the presence of a parasite in the…
Catheter-related bloodstream infections (CRBI) are nosocomial infectious complications associated with the use of intravascular catheters. Clinically manifested by local inflammatory changes (swelling, soreness, hyperemia in the catheter area) or generalized infection (febrile fever, chills, bacteremia). For laboratory confirmation of CRBI, blood is seeded for hemoculture and microbiological examination of the vascular catheter. At the first…
Karelian fever is an acute natural focal viral infection (the causative agent is the Edsbyn 5/82 virus) with a transmissible transmission mechanism. The clinical course of Karelian fever is characterized by feverish intoxication syndrome, arthralgia, polyarthritis, skin rashes. The diagnosis of Karelian fever is based on the data of epidanamnesis and serological examination, which demonstrates…
Capillariasis is helminthiasis caused by roundworms (nematodes). The most common is a parasitic intestinal lesion with a predominance of diarrheal syndrome in the clinic. Lung and liver lesions are also possible, manifested by fever, cough, jaundice of the skin and sclera, respectively. The only method of confirming diagnosis is microscopic detection of the pathogen in…
Isosporiasis is an anthroponotic protozoal infection with a fecal–oral transmission mechanism, characterized by damage to the gastrointestinal tract and the development of exicosis. There is the appearance of symptoms of gastroenterocolitis, possibly hemocolitis. The main method of diagnosis is the detection of oocysts in the fecal smears of patients. Additionally, serological methods for detecting infection…
